x86/kernel/ebda.c

1 // SPDX-License-Identifier: GPL-2.0
10  * This function reserves all conventional PC system BIOS related
15  * The BIOS places the EBDA/XBDA at the top of conventional
20  * guess the reserved BIOS area by looking at the low BIOS RAM size
26  * - This code also contains a quirk for Dell systems that neglect
29  * - The same quirk also avoids a problem with the AMD768MPX
34  * - Plus paravirt systems don't have a reliable value in the
35  *   'BIOS RAM size' pointer we can rely on, so we must quirk
46  * Using memory that is in use by the BIOS or by some DMA device
47  * the BIOS didn't shut down *is* a big problem to the kernel,
61 	 * NOTE: In a paravirtual environment the BIOS reserved  in reserve_bios_regions()
70 	 * BIOS RAM size is encoded in kilobytes, convert it  in reserve_bios_regions()
71 	 * to bytes to get a first guess at where the BIOS  in reserve_bios_regions()
89 	 * If the EBDA start address is sane and is below the BIOS region,  in reserve_bios_regions()
91 	 * the BIOS region.  in reserve_bios_regions()
97 	memblock_reserve(bios_start, 0x100000 - bios_start);  in reserve_bios_regions()